Class: BE210
Group: W4
Members: Gregory Moy, Rhonda Quain, Akshay Sateesh, Joyce Yang
Date: May 7, 1999
Abstract:
The main objectives of this experiment were (1) to compare the titration
curves and the numbers of ionizable residues in ovalbumin to those obtained
from literature, (2) to determine whether ovalbumin is reversible by comparing
titration curves of pH 2 to 12,12 to 2, 7 to 2, and 7 to 12, and (3) to
determine the optimum pH range of reversibility. Reversibility is
expected if the addition of an acid to the protein causes the titratable
sites to be ionized, changing the pH accordingly, and then the addition
of a base to this same protein solution causes the reverse to occur. By
comparing different titration curves, it was deduced that any titration
above or below this pH range would permanently deform the protein, and
would result in it being irreversible; however, any titration within the
pH range of 2 to 12.4 yielded the same titration curve. The number
of ionizable sites were calculated and compared to the theoretical ionizable
sites obtained from literature to determine the conformation of ovalbumin
at a certain pH with respect to a particular amino acid. It was found
that such conformational changes cannot be predicted as the number of ionizable
sites differed depending on the start and end point of the titration